NRSC 4132 Blog

Presently, we live in a society that has become increasingly dependent of pharmaceuticals as the great panacea for our discomforts and diseases. Treatment of neurological disorders is most commonly mediated through trial and error dosing of medication. This trend has steadily increased since the 1950s with the use of antidepressants and accompanied the closing of most of America?s mental hospitals. The emphasis on personal treatment and therapy has lost ground to the administration of singular chemicals (or combinations) that alter pathways with predicted but not completely understood chemical results (due to the highly interconnected nature of these chemical pathways.) This method can work wonders, many patients with severely debilitating neurological disorders such as schizophrenia often find great relief in their treatments and are able to live without or with minimal assistance. Drugs are also often a cheaper solution to the problem (compared to high levels of therapy or institutionalization.)
Unfortunately though this practice of pharmaceutical treatment has many limits; Many antidepressants that have been prescribed over the years have been found later to increase suicidal tendencies. Some people have genetic or environmentally caused dispositions that increase or decrease the drug potency or its negative side effects. Some drugs are sought out not for curing disorders or diseases but for recreational or ability enhancing uses (like the highly prevalent the misuse of adderall among students.) Then, of course, there are disorders or injuries which impair the nervous system for which there is no known treatment or specific biochemical pathway on which to act upon. For these reasons many scientists and clinicians are using nonpharmacological treatments, especially the utilization of sensory input, to help ease and heal their patients.
A great leader in this movement towards alternative forms treatment is Dr. V. S. Ramachandran. Dr. Ramachandran is a neuroscientist at the University of California San Diego and has helped people suffering with a strange neurological disorder known as phantom limb syndrome without surgery or drugs. Phantom limb syndrome is the experience of feeling of the presence of an amputated limb, it can be quite painful and is believed to be caused by lack of feedback inhibition (the brain tells the missing hand to clench but the hand cannot clench so the brain tells the hand to clench harder etc.) By using a ?mirror box? Ramachadran has found that he can use external sensory input (the patient ?seeing? his missing hand clench by using the reflection of his present hand) to override the jammed signal.
Another example of novel drug-free therapies has been the use of electrodes to serve as external sensory devices in both the treatment of vestibular malfunction and to return sight to the blind. A grid of electrodes is used in both cases and can be used as a sort of balancing meter for vestibular treatment or as a sort of low resolution black and white television (with an on electrode being white and an off electrode being black.) These treatments have shown success for many patients and may become more popular as technology advances.
These exciting and alternative therapies are of course limited, but may open the door to other forms of treatment for difficult to medicate neurological disorders.

As people we all vary in personality, thought and emotion. We all know that. But, when it comes to the world we live in, does everyone see the same things? If I look at a beautifully orange colored flower, does the person sitting next to me see what I see? According to a study by Dr. Samuel Schwarzkopf the answer to this question may be no.

In Dr. Schwarzkopf's recent study, a negative correlation was found between the size of an individual?s central visual field, as defined as the surface area of a person's primary visual cortex (V1), and the magnitude of illusory perceptual effect of two different optical illusions. The first optical illusion is the Ebbinghaus illusion where two central circles are identical in size but appear to be different sizes to the viewer because of the surrounding circles. One circle is surrounded by 6 larger circles and the other surrounded by 8 smaller circles. The second illusion come from Ponzo and is an illusion in which two checkerboard circles are identical in design and size but appear different because of the three dimensional background.

The two illusions may have different mechanisms behind their perception. The article predicts that the Ebbinghaus illusion may be associated with the lateral connections in V1 and the Ponzo illusion mediated by "feedback projections from the areas that extract the three dimensional context of the background".

The subjective experience of how large the circles looked varied between subjects. As I previously stated, in a large sample population, Schwarzkopf found a significant negative correlation between the magnitude of both illusions and the surface area of V1. Using standard retinotopic mapping procedures with functional magnetic resonance imaging (fMRI), participants with a small functionally defined V1 surface area were found to have stronger perceptual illusion than subjects with a large V1. There was no significant correlation found between the V2 or V3 visual regions and magnitude of the size illusions.

The study mentions that future work will look into whether the individual differences found can be attributed only to V1 surface area size or whether other mechanisms such as the concentration of the inhibitory neurotransmitter GABA or possible differences in actual brain structure. Furthermore, individual differences in size perception exist but are there commonalities among similar populations? For example: do people with autism see sizes more similarly than when an autistic person is compared to a person with brain activity attributed with normality? What about the effect of color blindness on size perception?

Schwarzkopf's study helps remind us of the variations in brain structure that contribute to each of us being who we are. If we all see things differently, how does the way we see something affect how we feel about it?

The article detailing Schwarzkopf?s study can be found in Nature Neuroscience at http://www.nature.com/neuro/journal/v14/n1/full/nn.2706.html